Federal and State legislation require control of vehicle exhaust emissions. Oxides of nitrogen (NOx) are one of the exhaust gas emissions that must be controlled. Formation of NOx will occur at higher combustion temperatures. In order to reduce the occurrence of the formation of NOx gases, exhaust gas recirculation systems have been developed which effectively reduce combustion temperatures and control emissions. Exhaust gas recirculation systems work by recirculating a portion of the exhaust gas from an engine back to the intake manifold where it can be combined with incoming air. When the mixture is compressed and ignited in the cylinder the result is a lower combustion temperature and the reduction of NOx. In order to make the recirculation of exhaust gas possible exhaust gas recirculation systems use exhaust gas recirculation (EGR) valves to open and close the conduits that recirculate the exhaust gas back to the intake manifold of the engine.
FIG. 1 is a cross-sectional view of a conventional EGR valve assembly having a valve body and actuator portion that are separate from the intake manifold. As shown, an actuator/valve assembly 1 has a valve body 2 and an actuator housing 3 connected together. The actuator housing 3 has an electrical connecter 4 that supplies energy to a motor 5 and a position sensor 6. The actuator housing 3 is aligned and connected to the valve body 2 using fasteners 7 and alignment pins 56. A seal 8 such as a paper-metal gasket is disposed between the valve body 2 and the actuator housing 3 in order to protect the actuator/valve assembly 1 from the outside environment and limit thermal transfer between the valve body 2 and housing 3. The EGR valve is then connected in some fashion to conduits that lead to the intake manifold of an engine. Sometimes the EGR valve body itself is bolted onto the intake manifold.
The use of EGR valves decreases the amount of space available in an engine because the EGR valve is another component that must be connected to an engine compartment. Therefore, it is desirable to develop EGR valves that take up minimal space. Additionally, it is also desirable to be able to remove the actuator portion of the EGR valve from the valve body in a manner will allow valve components to remain in their respective positions while allowing the actuator and actuator related components to be removed. This provides ease of servicing the actuator portion of the EGR valve. Additionally, it also provides an easy way of accessing the components of the valve body. Additionally there are manufacturing benefits to having an actuator portion that can be easily connected to or detached from the valve portion and its respective components.